I work as technician in a Singapore semiconductor factory. Here I share my working life as technician.
In the chamber, heater is the most critical part, not only does hot surface makes the deposition at faster rate, but evenness of the heater to make sure the deposition of metal is equallly onto the whole wafers.
This is how it looks like , a wafer sitting on a heater.
When we dismantled out the heater, rough gauge is by using a ruler, though not a good one. You will roughly get whether the surface is flat or not.
Another factor that play a part is the side groove. The screw need to install in nicely.
Another angle of the wafer holder sitting on the dismantled heater.
Top view of the heater , this is a good one , just need to polish a bit on surface with scotch bright.
Alien to me.. but I know many skills and knowledge within it.. bravo bro